Hydrocarbon fuel compositions

ABSTRACT

Carboxylic acid salts of polyamides having at least one amino group and hydrocarbon fuel compositions containing same. The salts are formed by neutralizing with a carboxylic acid at least 10% of the amino groups of a polyamide containing from about 2 to about 6 amide groups and at least one amino group. Hydrocarbon fuel compositions containing these salts exhibit desirable properties such as enhanced carburetor detergency and carburetor anti-icing characteristics, improved water tolerance, improved anti-corrosion properties, and cleaner engine operation.

United States Patent Badin et al.

HYDROCARBON FUEL COMPOSITIONS Inventors: Elmer J. Badin, l-lighstown;Paul M.

Kerschner, Trenton; Aldo Cresti, New Brunswick, all of NJ.

Cities Service Oil Service Company, Tulsa, Okla.

Filed: Apr. 18, 1973 Appl. N0.: 352,841

Related US. Application Data Division of Ser. No. 77,041, Sept. 30,1970, Pat. No. 3,765,850.

Assignee:

US. Cl 260/404.5; 252/515 A Int. Cl. C07c 103/30 Field of Search260/4045 References Cited UNITED STATES PATENTS [451 May 20, 19753,219,666 11/1965 Norman et a1 260/4045 X 3,224,893 12/1965 Floyd et a1260/4045 X 3,232,896 2/1966 Bell et a1 260/4045 X 3,462,284 8/1969Vertnik 260/4045 X Primary ExaminerLewis Gotts Assistant ExaminerEthelG. Love Attorney, Agent, or FirmEdwin T. Yates; John W. Carpenter; J. J.Ward [57] ABSTRACT Carboxylic acid salts of polyamides having at leastone amino group and hydrocarbon fuel compositions containing same. Thesalts are formed by neutralizing with a carboxylic acid at least 10% ofthe amino groups of a polyamide containing from about 2 to about 6 amidegroups and at least one amino group. Hydrocarbon fuel compositionscontaining these salts exhibit desirable properties such as enhancedcarburetor detergency and carburetor anti-icing characteristics,improved water tolerance, improved anti-corrosion properties, andcleaner engine operation.

7 Claims, No Drawings HYDROCARBON FUEL COMPOSITIONS This is a divisionof application Ser. No. 77,041, filed Sept. 30, 1970, now US. Pat. No.3,765,850.

BACKGROUND OF THE INVENTION Normally liquid hydrogen fuels often requireadditives to improve their performance characteristics. Thus, in fuelssuch as gasoline, diesel fuel and jet fuel, various additives areemployed to inhibit corrosion and to assist in maintaining cleanlinessin the carburetor and fuel intake system and to prevent carburetoricing. The additives vary in effectiveness, and it is often necessary touse a number of additives in a single composition.

Many additives for hydrocarbon fuels are only marginally soluble inhydrocarbons. Furthermore, they are often employed in concentrationsthat approach their limits of solubility. As a result, hydrocarboncompositions containing such additives often exhibit poor stability and,as a result, the additive may precipitate on standing.

In addition, many additives for hydrocarbon fuels have poor watertolerance. When fuel compositions containing such additives come incontact with water as, for example, in storage tanks, water enters thehydrocarbon phase. This is particularly deleterious in jet fuels. Thetemperatures at high altitudes where jet aircraft operate are well belowfreezing. Hence, water in the fuel crystallizes and plugs fuel filters,thereby cutting off the flow of fuel to the engines. To combat this,fuel tank heaters and additives to prevent ice formation are employed.

SUMMARY OF THE INVENTION It is an object of this invention to provideadditives which, when incorporated in normally liquid hydrocarbon fuels,impart desirable properties thereto.

It is another object of this invention to provide additives which arereadily soluble in normally liquid hydrocarbon fuels to produce stablecompositions.

It is yet another object of this invention to provide normally liquidhydrocarbon fuel compositions having enhanced carburetor and fuel intakesystem detergency properties as well as superior carburetor anti-icingcharacteristics.

Another object of this invention is to provide normally liquidhydrocarbon fuel compositions having improved anti-corrosion properties.

It is still another object of this invention to provide normally liquidhydrocarbon fuel compositions having improved water toleranceproperties.

Still other objects will appear hereinafter.

The foregoing objects are attained in accordance with this invention. Ingeneral, this invention comprises a carboxylic acid salt of a compoundhaving the general formula wherein m is at least 1 and the sum ofn plusm is from 2 to about 6, R is a multivalent hydrocarbon group of about 2to about 52 carbons, R is a hydrocarbylene group of about 2 to about 12carbons, R" is selected from the group consisting of hydrogen andhydrocarbyl groups of about 1 to about 30 carbons, R is a hyrocarbylgroup of about 2 to about 12 carbons, and at least 10% of the aminogroups are converted to the carboxylic acid salt; and

normally liquid hydrocarbon fuel compositions comprising a majorproportion of a normally liquid hydrocarbon fuel and a minor proportionof the above additive.

Normally liquid hydrocarbon fuel compositions containing the additivecompounds of this invention exhibit such desirable properties asimproved anticorrosion properties and enhanced carburetor and fuelintake system detergency properties as well as superior carburetoranti-icing characteristics. In addition, hydrocarbon fuel compositionscontaining our additives have good water tolerance which favors dryfuel. Furthermore, the good solubility of the additives of thisinvention in liquid hydrocarbon fuels insures stability with littletendency toward precipitation. Another advantage of our additives istheir ability to impart desirable properties to liquid hydrocarbon fuelswhen used at low concentrations which makes them economicallyattractive. Other advantages of this invention will be apparent from thefollowing description.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The normally liquid hydrocarboncompositions of this invention are prepared by incorporating into amajor proportion of a normally liquid hydrocarbon fuel a minorproportion of an additive which is basically a carboxylic acid salt of apolyamide having at least one amino group. Examples of normally liquidhydrocarbon fuels that have desirable properties imparted thereto by theadditives of this invention are gasoline, jet fuel and diesel fuel.

The novel additives of this invention are prepared by reacting acarboxylic acid with a polyamide containing from 2 to about 6 amidegroups and at least one amino group whereby at least about 10% of theamino groups are converted to the carboxylic acid salt. The polyamidesare prepared by condensing a polycarboxylic acid having from 2 to about6 carboxyl groups with an amine or amines to convert each carboxyl groupto the corresponding N-substituted amide group. It is critical that atleast one N-substituted amide group in every molecule contain an aminogroup on the substituent. Thus at least one carboxyl group of thepolycarboxylic acid must be condensed with a polyamide, preferably adiamine, while the remainder of the carboxyl groups may be condensedwith either a monoamine or a polyamine. However, it is preferred thateach carboxyl group be condensed with a diamine. The preferred acids aredicarboxylic acids. Hence the preferred polyamides are diamino-diamideshaving the general formula R" O O u n I R"2N -R' N C R C N R'- NR"2wherein R is a hydrocarbylene group of about 2 to about 52 carbons andpreferably about 4 to about 34 carbons, R is a hydrocarbylene group ofabout 2 to about 12 carbons and preferably about 2 to about 6 carbons,and R" is selected from the group consisting of hydrogen and hydrocarbylgroups of about 1 to about 30 carbons and preferably about 3 to about 24carbons.

The carboxylic acid which is reacted with the polyamide containing oneor more amino groups to form the salt may contain from 1 to about 3carboxyl groups and from about 1 to about 36 carbons and may bealiphatic, aromatic, or naphthenic or it may contain various mixtures ofaliphatic, aromatic and naphthenic segments. Aliphatic and naphthenicsegments may be either saturated or unsaturated. The carboxylic acid mayalso contain one or more hydroxyl or hydrocarbyloxy groups. The hydroxyland hydrocarbyloxy groups may be on an aliphatic, naphthenic or aromaticsegment of the carboxylic acid. The ratio of carboxylic acid to thepolyamide containing one or more amino groups is such that at leastabout of the amino groups are converted to the carboxylic acid salt.While about 10% to about 100% of the amino groups may be converted tothe carboxylic acid salt, it is preferred that about 50% to about 90% ofthe amino groups be converted to the salt since the presence of somefree amino groups is usually desirable.

As stated above, the polyamide containing from 2 to about 6 amide groupsand at least one amino group has the general formula wherein R is amultivalent hydrocarbon group of about 2 to about 52, and preferablyabout 4 to about 34, carbons, and m is at least one and the sum of nplus m is from 2 to about 6. The polycarboxylic acid from which thepolyamide is made therefore has the general formula wherein R is amultivalent hydrocarbon group of about 2 to about 52 carbons andpreferably about 4 to about 34 carbons. R may be aliphatic, aromatic ornaphthenic, or it may contain various mixtures of aliphatic,

aromatic and naphthenic segments. Aliphatic and naphthenic segments maybe either saturated or unsaturated. While the sum of m plus n may befrom 2 to about 6, it is preferred that the sum of m plus n be 2,

' tWO i.e., a dicarboxylic acid. Examples of suitable polycarboxylicacids are succinic acid, glutaric acid, adipic acid, terephthalic acid,1,4-cyclohexanedicarboxylic acid, pyromellitic acid,1,l8-dicarboxyoctadecane, and trimer acid which is the trimer of apolyunsaturated C monocarboxylic acid, being a C tricarboxylic acid ofuncertain structure. The preferred polycarboxylic acid is a dimer acidproduced by the dimerization of a polyunsaturated C monocarboxylic fattyacid to produce an unsaturated C dicarboxylic acid whose exact structureis not known with certainty. Such a dimer acid is produced by EmeryIndustries, Inc. under the trade name of Empol 1014.

The amine which is condensed with the polycarboxylic acid to form thepolyamide is selected from the group consisting of monoamines andpolyamines, preferably diamines, having the general formulas wherein Ris a hydrocarbylene group of about 2 to about 12 carbons and preferablyabout 2 to about 6 carbons, R" is selected from the group consisting ofhydrogen and hydrocarbyl groups of about 1 to about 30 carbons andpreferably about 3 to about 24 carbons, and R is a hydrocarbyl group ofabout 2 to about 12 carbons and preferably about 2 to about 6 carbons.R, R, and R" when it is a hydrocarbyl group, may be aliphatic, aromaticor naphthenic or they may contain various mixtures of aliphatic,naphthenic and aromatic segments. Aliphatic and naphthenic segments maybe either saturated or unsaturated. Examples of suitable monoamines arediethylamine, dodecylamine, cyclohexylamine, methylbutylamine andpropylamine. Examples of suitable diamines are ethylenediamine,propylenediamine; 1,12-diaminododecane; hexamethylenediamine; N-methyl-N-propyl-l ,3- propylenediamine; N,N-dibutylethylenediamine; 1,4-diaminohexane; N-oleyl-1,3-propylenediamine; and N-cyclohexylethylenediamine. The preferred amine is N-(10-phenylstearyl)-l ,3-propylenediamine.

Examples of carboxylic acids which are useful for salt formation areformic acid, acetic acid, benzoic acid, hexahydrobenzoic acid, dimeracid, tartaric acid, citric acid, gluconic acid, oleic acid, salicyclicacid, 10- phenylstearic acid, p-methoxybenozic acid, lactic acid,alpha-butoxyvaleric acid, and adipic acid. The preferred acid islO-(hydroxyphenyl) stearic acid.

In order that the additive of our invention have the necessarysolubility in hydrocarbon fuels, it is necessary that the polyamidecontaining from 2 to about 6 amide groups and at least one amino groupcontain about 24 to about 100, and preferably about 30 to about 90,carbons. Since the preferred acid for amide formation is dimer acid, thepreferred amine is N-( 10- phenylstearyl)-1,3-propylenediamine, and thepreferred acid for salt formation is lO-(hydroxyphenyl) stearic acid,the preferred additive of our invention is the l0-(hydroxyphenyl)stearicacid salt of the diamide obtained by condensing one mole of dimer acidwith moles v of N-( l0 phenylstearyl)-l ,3- propylenediamine. It will beunderstood that when the dimer acid condenses with the diamine to formthe diamine-diamide, either amino group may condense with a carboxylgroup and the product is therefore largely a mixture of the followingisomers and H il O H l i II II I I R N (CH C R C N (CH NH wherein R isthe C hydrocarbylene portion of the dimer acid and R is al0-phenylstearyl group. The ratio of l0-(hydroxyphenyl)stearic acid tothe diaminodiamide to form our preferred additive is such as to convertfrom about to about 100%, and preferably about 50% to about 90%, of theamino groups of the diamino-diamide to the l0-(hydroxyphenyl)stearicacid salt.

While the concentrations of the additives of this invention inhydrocarbon fuels may be varied over a broad range, hydrocarbon fuelcompositions containing from about 1 to about 100 pounds of additive perthousand barrels (PTB) of the composition are generally used. However,hydrocarbon fuel compositions containing from about 4 to about 50 PTB ofadditive are preferred.

The efficacy of our additives in hydrocarbon fuel compositions isdetermined by subjecting the compositions to one or more of thefollowing tests. The tests and their procedures are as followsCarburetor Detergency Test Engine blow-by contaminants are generated inan engine and collected in a flask. At the end of the collection periodthe water phase is separated from the fuel phase, the latter beingdiscarded. The water phase of the contaminants is used for thecarburetor detergency evaluations.

The carburetor detergency test is run on a Cooperative LubricantsResearch (CLR) engine, a single cylinder research engine manufactured byLaboratory Equipment Company. The contaminants are injected into thethrottle body of a CLR engine running with a rich mixture and on whichthe throttle plate has been removed and a 200 mesh stainless steelscreen installed near the entrance to the intake manifold. The amount ofdeposits accumulated on the screen after three hours of engine operationindicates the detergency performance of the fuel. Experimental fuels,with reference and base fuel runs, are tested with the same batch ofcontaminants.

At the conclusion of the three hour run, the 200 mesh screen is removedand evaluated for contaminant accumulation. The reflectance of thescreen, determined by means of a reflectance meter, is a measure of theamount of deposits accumulated on the screen. The higher thereflectance, the cleaner the screen, i.e., the lower the accumulation ofdeposits.

The effectiveness of an additive is represented as the ratio, expressedas a percentage, of the average screen reflectance for the fuelcontaining the additive to the average screen reflectance for a basefuelcontaining no detergency additive. Thus an experimental additivethat equals the performance of the base fuel will have an effectivenessof an experimental additive that performs at a lower level than the basefuel will have an effectiveness of less than 100%, and an experimentaladditive that performs at a higher level than the base fuel will have aneffectiveness of greater than 100%. Carburetor Anti-Icing Test The testis run on a CLR single cylinder engine coupled to a speed controldynamometer. The engine is fitted with a special, thermally-isolatedcarburetor with external float bowls; no idle fuel system is used. Thecarburetor has an adjustable main jet and the throttle body isconstructed of glass or clear plastic so icing can be confirmed byvisual inspection. A temperature and humidity control system suppliesinlet air to the carburetor at the desired conditions and also to aglass or clear plastic box enclosing the carburetor.

The anti-icing additives are evaluated in a base fuel comprisinggasoline containing 3 ml./gallon of tetraethyllead. A non-icing purgefuel consisting of the base fuel containing 5.5% of isopropyl alcohol isused in the test. The anti-icing properties of gasoline compositionscontaining additives of this invention are compared to those of the basefuel containing no anti-icing additive.

Ice formation on the throttle plate of the carburetor is measured by anincrease of manifold vacuum caused by a choking of the engine by the iceformation. The time in seconds for manifold vacuum to increase 1.5 and2.0 inches of mercury are recorded as time to ice with the fuel which isbeing evaluated. An increase in manifold vacuum of 1.5 inches of mercuryis defined as trace ice and an increase in manifold vacuum of 2.0 inchesof mercury is defined as severe ice.

Engine operating conditions are set so as to cause a reference fuel,i.e., a base fuel containing a reference anti-icing additive, to icesufficiently to cause a 2.0 inch manifold vacuum increase in 40 to 50seconds. When these conditions are set, the base fuel containing noanti-icing additive will ice to the same extent in 18 to 20 seconds.Once these operating conditions have been achieved, the anti-icingcharacteristics of base fuel containing the experimental additives canbe evaluated.

In running the test on a'fuel composition containing an experimentaladditive, once ice severe enough to raise the manifold vacuum 2.0 inchesof mercury has formed, the carburetor is switched to the purge fuelwhich removes the ice. After 50 seconds to allow for ice removal andengine stabilization, the carburetor is switched back to theexperimental fuel. The above procedure is repeated until five runs onthe experimental fuel have been made, the time for manifold vacuumincreases of 1.5 and 2.0 inches of mercury being noted. The times of thefive runs are then averaged for each manifold vacuum increase. Either abase fuel or a reference fuel is run after every two experimentaladditive runs.

Water Tolerance Test Into an 8 oz. bottle are poured 100 ml. of the fuelcomposition to be tested plus 20 ml. of distilled water. The bottle iscapped and hand-shaken with an up-down motion for 2.5 minutes,approximately 180 to 200 times. The mixture is stored in the dark on avibrationfree table for 24 hours and is then rated. The interface israted numerically according to accumulations of skin, dirt, bubbles andemulsion and the numbers range from O to 7. A rating of denotes a cleanbreak at the interface with no accumulations of any kind. A rating of 7denotes that the water phase is occupied completely by emulsion. Variousdegrees of accumulations at the interface are thus assigned numericalvalues ranging from 0 for no accumulation to 7 for the poorest rating.Finer variations in the ratings may be denoted by and signs after thenumerical rating. Thus a rating of 2 is slightly better than a rating of2 while a rating of is slightly poorer than a rating of 5. In addition,both the fuel phase and the water phase are rated for clarity as followsC very clear, no haze SH slightly hazy H hazy VH very hazy E emulsionPassing ratings for a fuel composition are an interface rating of O to 2and fuel and water phase clarity ratings of C.

Corrosion Test The test is run using 300 ml. of a fuel compositioncomprising 75 volume percent of ASTM grade isooctane and 25 volumepercent of reagent grade toluene in contact with ml. of an aqueous saltsolution containing 4 weight percent NaCl. The fuel-salt water mixtureis placed in a 400 ml. flask thermostatted at 80F. and an electrodeassembly is inserted through the neck of the flask and immersed in thefuel-water mixture. The electrode assembly consists of a centralplatinum conductor to which are attached, through an insulator, twostrips of 1010 carbon steel in an inverted V fashion. Each steel stripis 2 in. long by A; in. wide by 2 mils thick. The free end of each steelstrip is separately connected by an insulated conductor to an externalcircuit consisting of a millivoltmeter, a 1.5 volt DC power source, andthe common central electrode. This system permits millivolt readings tobe obtained in duplicate, one for each strip, at any given time.

The percent corrosion is determined as follows. The fuel-salt watermixture, thermostatted at 80F., is stirred and the millivolts at thestart are determined for each strip and the two results are averaged(C,,,. At time t the average millivolts (C are again determined. Thecumulative value (C at time t is defined by cum. rny/ ary.

The corrosion is determined from the expression Corrosion (lC )100.

The percent corrosion may be thus determined for the unmodified basefuel and for fuel compositions containing anti-corrosion additives.

Additional visual indications of corrosion are the formation of a brownrust dispersion in the fuel-salt water mixture and severe pitting of thesteel strips.

The following specific examples will serve to better illustrate ourinvention.

EXAMPLE I A solution of 1 mole of Empol 1014 dimer acid in toluene isplaced in a flask fitted with a stirrer, a dropping funnel, a Dean-Starktrap and a reflux condenser. To the stirred solution maintained at atemperature of 24-31C are added 2 moles of N-( l0-phenylstearyl)-1,3-propylenediamine over a 2 hour period. The stirred mixture is heatedunder reflux until 36 ml. of water, the theoretical amount for formationof the mixture of isomeric diamino-diamides, are collected in the Dean-Stark trap. The toluene solution contains 34.3 weight of the isomericdiamino-diamides.

Various carboxylic acid salts of the above isomeric diamino-diamides areprepared as follows. The desired amount of the carboxylic acid is addedto 200 g. of the above toluene solution of diamino-diamides, each 200 g.of solution containing 68.6 g. of diamino-diamides and 103 meq. of aminogroups. The mixture is stirred at room temperature followed by removalof toluene by distillation under reduced pressure to yield thecarboxylic acid salt of the isomeric diamino-diamides. Table 1 lists thesalt-forming carboxylic acids, the number of milliequivalents of eachsalt-forming acid available to react with the 103 meq. of amino groupsin the isomeric diamino-diamides, the percent of amino groups of thediamino-diamides converted to the carboxylic acid salt, and the letterdesignation assigned to each additive product.

TABLE I Meg. of Meg. of Amino Salt-Fonning Salt-Forming lsomeric GroupsCarboxylic Carboxylic Diamino- Changed Additive Acid Acid Diamides toSalt Product.

l0-( hydroxy- 98.8 103 96 v a phenyl) stearic acid Empol 1014 I03 I03100 b dimer acid Empol 1014 51.6 103 50 c dimer acid oleic acid 103 103100 cl lO-phenyl- 103 I03 100 e stearic acid acetic acid 103 103 100 fEXAMPLE II A number of unleaded gasoline compositions containing theadditives of Example I are prepared and subjected to the water tolerancetest. As a reference, a base unleaded gasoline containing no additive isalso subjected to the test. The concentrations of the additives and theresults of the water tolerance tests on the gasoline compositions aregiven in Table 11.

From the data in Table II it can be seen that unleaded gasolinecompositions containing the carboxylic acid salts of the isomericdiamino-diamides of Example I pass the water tolerance test.

EXAMPLE III Gasoline compositions are prepared by dissolving adavailableadditive. ditives a and of Exam le I in a base asoline containf pEXAMPLE v ing 3 ml. TEL/gal. and the compositions are sub ected 1 to thecarburetor detergency test. For comparison pur- By the procedure ofExample I, various polycarboxposes, a base leaded gasoline containing noadditive ylic acids may be condensed with various diamines so other than3 ml. TEL/gal. and a leaded (3 ml. TEL/- that each carboxyl group of theacid condenses with 1 gal.) gasoline composition containing acommercially amino group of the diamine to form the N-substituted a b emulti-functimal additive, DMA-4 manupolyamide wherein each of thesubstituent groups confactured by DuPont Corporation, are also subjectedto tains the unreacted amino group. The reaction is reprethe carburetordetergency test. The make-up of the sented as follows gasolinecompositions and the results of the tests are given in Table III. Itwill be noted that the reflectance of 6.4 reflectance units for the 200mesh screen from the test on the base leaded gasoline is arbitrarily as-9 si ned an Effectiveness of 100%.

g R COH (m+n) HNR'NR" TABLE 111 m+n 2 Additive O Additive Concentration,PTB Reflectance Effectiveness R N l n 6.4 units 100.0 5 c R NR 2 (m+n)H2O DMA-4 15 25.7 401.6 m n It is seen from Table III that the additivesof this invenwherein R, R, R", m, and n are as defined previously. tionhave excellent carburetor detergency properties. Each of thepolyamino-polyamides can be reacted ac- TABLE V Amino GroupsPolycarboxylrc 4 SaltForming Converted Additive Acid Dramine CarboxylicAcid to Salt Product N-oleyl-1,3- succinic acid propylenediaminep-methoxybenzoic acid 30 g adipic acid l,l2diaminododecane formic acid60 h N'-cyclohexylterephthalic acid ethylenediamine adipic acid 80 itrimer acid ethylenediamine benzoic acid 40 j pyromellitic acid1,4-diaminohexane lactic acid 10 k 1,18-dicarboxyoctadecanehexamethylenediamine citric acid 70 l N,N-dibutylglutaric acidethylenediamine tartaric acid 85 m 1,4-cyclohexane- N(10-phenylstearyl)- l .3 alpha-butoxyvaleric 90 N dicarboxylic acidpropylenediamine acid 1 Empol 1014 dimer acid propylenediaminehexahydrobenzoic acid 75 0 EXAMPLE IV TABLE IV Average Seconds to Ice fManifold Manifold w Additive. Vacuum Vacuum Concentration, Increase,Increase, Additive V PTB 1.5 in. 2.0 in.

16.49 19.57 DMA-4 15 22.23 42.73 a 6 21.23 37.14 f 6 19.78 33.94

From Table IV it can be seen that the additives of this invention, whenincorporated in a base leaded gasoline, markedly improve the carburetoranti-icing properties thereof and compare favorably with a commerciallycording to the procedure of Example I with a carboxylic acid so that atleast 10% of the amino groups in the polyamino-polyamides are convertedto the carboxylic acid salt. Table V lists the various amide-formingpolycarboxylic acids, the diamines, the salt-forming carboxylic acids,the of the amino groups of the polyaminopolyamides converted to thecarboxylic acid salts, and the letter designation assigned to eachadditive product.

EXAMPLE VI Diamides may be prepared by condensing 1 mole of adicarboxylic acid with 1 mole of a monoamine whereby l carboxyl group isconverted to the amide and the other remains unchanged. Thisintermediate product may then be reacted with 1 mole of a diaminewhereby the remaining carboxyl group is condensed with 1 amino group ofthe diamine to yield a diamide having an amino group. The reaction isrepresented as follows O O R" R" O II II I I II II HO-C-R-C-OH .R''N-H-9 R '-N -C-R-COH H O R" O O R" R O O R" I '7 II I II II R' '-N-C-R-C-OH H-N -R'-NR" R' -N -C-R-C-N-R'-NR" H O wherein R, R, R and Rare as defined previously. EXAMPLE IX Each of the amino-diamides soformed can be reacted according to the procedure of Example I with acarboxylic acid so that at least of the amino groups in theamino-diamide are converted to the carboxylic acid salt. Table VI liststhe amide-forming dicarboxylic acids, the monoamines, the diamines, thesalt-forming carboxylic acids, the of the amino groups of theamino-diamides converted to the carboxylic acid salts,

Diesel fuel compositions containing the additives of this invention maybe prepared. Suitable compositions contain 10 PTB of additive a; 48 PTBof additive b; 18 PTB of additive c; 4 PTB of additive d; 2 PTB ofadditive e; 37 PTB of additive f; 15 PTB of additive k; 7 PTB ofadditive g; 12 PTB of additive i; 30 PTB of additive l; 17 PTB ofadditive n; 9 PTB of additive q; 40 PTB of additive s; or 13 PTB ofadditive p. These diesel and the letter designation assigned to eachadditive fuel compositions will have good anti-corrosion properproduct.ties and acceptable water tolerance. In addition, the

TABLE VI Amino Groups Dicarboxylic Salt-Forming Converted Additive AcidMonoamine Diamine Carboxylic Acid to Salt Product Empol l0l4 dimer aciddiethylamine ethylenediamine formic acid 75 p 1,]8-dicarboxymethylbutyl- N-methyl-N'-propyll0-(hydroxyphenyl) 90 qcctadecane amine l.3-propylenediamine stearic acid terephthalicN-oleyl-l ,3- acid cyclohexylamine propylenediamine gluconic acid 10 rl,4cyclohexane- N-( lO-phenylstearyl p methoxybenzoic dicarboxylic acidpropylamine l,3-propylenediamine ac 50 s N-o eyl-l,3- Empol l0l4dodecylamine propylenediamine dimer acid 100 t adipic acid EXAMPLE VIlLeaded (3 ml. TEL/gal.) gasoline compositions containing the additivesof this invention can be prepared by dissolving the additives in thebase leaded gasoline. Suitable compositions may, for example, contain 4PTB of additive a; 36 PTB of additive l; l PTB of additive f; 15 PTB ofadditive g; 50 PTB of additive r; 43 PTB of additive j; 8 PTB ofadditive m; 16 PTB of additive p; 3 PTB of additive k; l l PTB ofadditive s; or 20 PTB of additive i. The gasoline compositionscontaining these additives will have acceptable water tolerance andexcellent anti-corrosion properties. In addition, these compositionswill be found to have better carburetor detergency and carburetoranti-icing properties than does the base leaded gasoline.

EXAMPLE VIII Suitable unleaded gasoline compositions may be prepared bydissolving the additives of our invention in a base unleaded gasoline.The compositions may contain, for instance, 14 PTB of additive a; 5 PTBof additive q; PTB of additive h; 1 PTB of additive t; 9 PTB of additivee; 47 PTB of additive n; 15 PTB of additive c; 7 PTB of additive 0; 36PTB of additive s; ll PTB of additive l; or 40 PTB of additive k. Thecompositions containing the additives will be found to have superiorcarburetor anti-icing and carburetor detergency properties relative tothe base gasoline and, in addition, pass the water tolerance test. Thegasoline compositions will also have superior anti-corrosion properties.

fuel intake systems of diesel engines run on the above fuel compositionswill be found to be cleaner than the fuel intake systems of engines runon the base fuel containing no additive.

EXAMPLE X Jet fuel compositions may be prepared by dissolving theadditives of our invention in a base jet fuel. The compositions may, forinstance, contain 20 PTB of additive a; 3 PTB of additive d; 7 PTB ofadditive f; 49 PTB of additive g; 17 PTB of additive h; 38 PTB ofadditive j; 6 PTB of additive m; 11 PTB of additive 0; l4 PTB ofadditive q; 9 PTB of additive r; or 27 PTB of additive t. The jet fuelcompositions will have very good anti-corrosion properties and pass thewater tolerance test. Accordingly, jet fuel compositions containing theadditives of this invention will not tend to pick up water, resulting inreduced tendency toward ice formation and fuel filter plugging.

EXAMPLE XI Compositions are prepared by dissolving additives a andfofExample I in a base fuel comprising volume percent of ASTM gradeisooctane and 25 volume percent of reagent grade toluene, and thecompositions are subjected to the corrosion test. For referencepurposes, a sample of base fuel containing no additive is also subjectedto the corrosion test. The test is run for 44 hours. The concentrationsof the additives. and the percent corrosion after 44 hours for each fuelcomposition are given in Table VII.

1 3 TABLE Vll Additive Additive Concentration, PTB Corrosion it isapparent from the data in Table VII that the carboxylic acid salts ofamino-polyamides impart excellent anti-corrosion properties tohydrocarbon fuels when incorporated therein. Additional evidenceillustrating the effectiveness of a as an anti-corrosion additive isthat there is a complete absence of brown rust in the fuel-salt watermixture at the conclusion of the test, and microscopic examination showsthat there is practically no pitting of the steel strips at the end ofthe 44 hour test.

While the invention has been described above with respect to certainpreferred embodiments thereof, it will be understood by those skilled inthe art that various changes and modifications may be made withoutdeparting from the spirit and scope of the invention.

about 2 to about 52 carbons, R is a hydrocarbylene group of about 2 toabout 12 carbons, R" is selected from the group consisting of hydrogenand hydrocarbyl groups of about 1 to about carbons, R' is a hydrocarbylgroup of about 2 to about 12 carbons, and at least about 10% of theamino groups contained therein are converted to the carboxylic acidsalt.

2. The compound of claim 1 wherein R is a multivalent hydrocarbon groupof about 4 to about 34 carbons, R is a hydrocarbylene group of about 2to about 6 carbons, R" is selected from the group consisting of hydrogenand hydrocarbyl groups of about 3 to about 24 carbons, R' is ahydrocarbyl group of about 2 to about 6 carbons, and about 50% to about90% of the amino groups contained therein are converted to thecarboxylic acid salt.

3. The compound of claim 1 wherein n is zero and m is 2.

4. The compound of claim 2 wherein n is zero and m is 2.

5. A Carboxylic acid salt of a compound selected from the groupconsisting of H O 0 li H l R N (CH2)3N c R.C N (CH2)3 N R,

We claim: 1. A carboxylic acid salt of a compound having the formulawherein m is at least i and the sum of n plus m is from 2 to about 6, Ris a multivalent hydrocarbon group of R' O O R' N- (c11 N c- R- c N (c11NH2,

H O O R'

1. A CARBOXYLIC ACID SALT OF A COMPOUND HAVING THE FORMULA
 2. Thecompound of claim 1 wherein R is a multivalent hydrocarbon group ofabout 4 to about 34 carbons, R'' is a hydrocarbylene group of about 2 toabout 6 carbons, R'''' is selected from the group consisting of hydrogenand hydrocarbyl groups of about 3 to about 24 carbons, R'''''' is ahydrocarbyl group of about 2 to about 6 carbons, and about 50% to about90% of the amino groups contained therein are converted to thecarboxylic acid salt.
 3. The compound of claim 1 wherein n is zero and mis
 2. 4. The compound of claim 2 wherein n is zero and m is
 2. 5. ACarboxylic acid salt of a compound selected from the group consisting of6. The compound of claim 1 wherein the salt-forming carboxylic acidcontains a functional group selected from the group consisting ofhydroxyl and hydrocarbyloxy groups.
 7. The compound of claim 5 whereinthe salt-forming carboxylic acid is 10-(hydroxyphenyl) stearic acid.